Aphis nerii, commonly known as the oleander aphid, is a bright yellow aphid found on oleander plants. It is notable for its striking coloration and its ability to reproduce rapidly. These aphids form dense colonies and are primarily found in warm climates. They feed on plant sap and secrete a sticky substance called honeydew.

Aphis nerii, commonly known as the oleander aphid, is believed to have originated from the Mediterranean region. However, it has since spread to various parts of the world, including North America, South America, Africa, Asia, and Australia, primarily due to its association with ornamental plants like oleander.

The oleander aphid typically inhabits warm, temperate to subtropical regions where its host plants thrive. It is often found in gardens, parks, and areas where ornamental plants are cultivated. The species favors environments where its primary host plants, such as oleander (Nerium oleander), milkweeds (Asclepias spp.), and related species are abundant.

Aphis nerii occupies an ecological niche as a sap-sucking insect, feeding primarily on the phloem of its host plants. It plays a role in the ecosystem by serving as prey for various natural predators such as lady beetles, lacewings, and parasitic wasps. Its presence can also indicate the health and distribution of its host plants, influencing the dynamics of plant-insect interactions in its habitat.